It didn't happen in college, nor in high school, nor in any of Walt Harris' 150 previous NFL games. Instead, Sunday marked the first-ever three-interception game for the 49ers' cornerback.

In all, it wasn't a bad week for Harris. The 11-year veteran was named a defensive captain along with defensive lineman Bryant Young earlier in the week, and then followed it with a career game in a 34-20 win over the Raiders that was spearheaded by a spirited defensive effort.

Through five games, Harris easily is the 49ers' defensive MVP with three interceptions, a sack, two forced fumbles, a fumble recovery and eight passes defended.

Not bad for a guy who was released from the Redskins on March 10.

"I feel very comfortable playing with this organization and this defense," said Harris, who reached a deal with the 49ers while he was on a Mexican cruise with his wife, Trina.

Harris says that the 49ers allow him to do what he does best and don't bog him down with lots of instruction on technique.

Harris said he feels revived, and never has he felt like such a leader.

"They told me that would be part of my role when I got here," Harris said. "I like the pressure."

Harris' first two interceptions were gifts from Raiders quarterback Andrew Walter, who threw the ball right to Harris. On Harris' last interception, he baited third-string quarterback Marques Tuiasosopo into throwing a little jump pass, which was intended for Randy Moss. Harris got in front of Moss and out-jumped him for the ball.

Increasingly, Harris is making the Redskins look foolish. Not only did they release Harris, who apparently has a lot left, they also traded for defensive back Mike Rumph, a first-round bust for the 49ers.

Rumph was dealt for wide receiver Taylor Jacobs on Aug. 14. So far, Rumph has made eight tackles and hasn't gotten his hands on the ball as a backup corner for the Redskins.

Harris has played so well, his fellow defensive backs feel no shame in expressing their envy.

"He's got too many (picks)," safety Mike Adams said. "He could have spread that out. You know what I'm saying?"

The three interceptions -- matching his total of the past three years -- could have been a result of an increased emphasis on third-down defense during practice. The 49ers, who didn't have an interception this season before Sunday, devoted more practice time to third down after being ranked 29th in third-down efficiency following the 41-0 debacle the previous Sunday in Kansas City.

Lawson tipped a Walter pass on 3rd-and-8 at the beginning of the fourth quarter that was intercepted by safety Chad Williams. The 49ers also limited Oakland to three first downs in nine third-down opportunities.

Harris and the 49ers benefited from a fine game plan. Walter, a second-year player making his second career starts, appeared flummoxed by the 49ers' constantly shifting defense on passing downs.

Typically, the 49ers send out six defensive backs on passing downs and they all seem to take turns running into gaps and backing off. It forced Walter to call a timeout on 3rd-and-4 in the first quarter.

After that, Walter went on a quick count on third downs, which didn't allow him to audible to different plays.